Gas heaters



Jan. 10, 1967 Mp0. LAWSON 3,297,019

GAS HEATERS Original Filed July 24. 1963 INVENTOR. MAURICE O. LAWSON BY fawn; ffilavru ATTORNEY United States Patent 3,27,0l9 GAS HEATERS Maurice U. Lawson, 119 Rubicon Road, Dayton, Ohio 454% Original application July 24, 1963, Ser. No. 297,339, new

Patent No. 3,245,399, dated Apr. 12, 1966. Divided and this application Feb. 10, 19nd, Scr. No. 526,458

13 Claims. ((11. 126-247) The present invention is a division of that disclosed in my co-pending application for United States Letters Patent Serial No. 297,389 filed July 24, 1963, now Patent No. 3,245,399, the latter in turn being a continuation in part of United States Letters Patent Serial No. 107,598, filed May 3, 1961 and now abandoned.

This invention relates to a gas heater and more particularly to a recirculation type continuous flow heat pump. It has prime utility when embodied in a heater for automotive vehicles and will be so described. However, neither the application nor the form of its embodiment need be so limited. Such is certainly not intended.

A primary object of the present invention is to provide a gas heater which may be economically fabricated, more efficient and satisfactory in use in a wide variety of applications and unlikely to malfunction.

A further object of the invention is to provide a continuous fiow heat pump capable of producing a substantial rise in a gas temperature in a relatively short period of time.

Another object of the invention is to provide a small, compact, continuous flow heat pump which can achieve a high degree of operating efficiency after a very brief interval of operation.

Another object of the invention is to provide a heater having particular advantages for use in automotive vehicles or the like and one which can achieve substantially one hundred percent operating efiiciency.

An additional object of the invention is to provide a single stage recirculation type heater so designed as to overcome substantially all losses as normally occur in conventional heater operation.

Another object of the invention is to provide a recirculation type gas heater which can achieve a satisfactory heat flow in a matter of seconds.

An additional object of the invention is to provide a gas heater possessing the advantageous structural features, the inherent meritorious characteristics and the mode of operation herein described.

With the above and other incidental objects in view, as will more fully appear in the specification, the invention intended to be protected by the present Letters Patent consists of the features of construction, the parts and combinations thereof, and the mode of operation as hereinafter described or illustrated in the accompanying drawings, or their equivalents.

Referring to the accompanying drawing wherein are shown some but obviously not necessarily all the forms of embodiment of the invention,

FIG. 1 schematically shows a cross section of a gas heater utilizing an axial flow rotor in a form and manner to embody the invention principles; and

FIG. 2 shows a generally schematic cross sectional view of a modification of the invention as illustrated in FIG. 1.

Like parts are indicated by similar characters of reference throughout the several views.

It is well known that the power absorption of an axial flow rotor or radial flow rotor can be very high, even when designed for the specific purpose of compressing a gas. For example, an axial flow compressor rotor having a power absorption of 24 HP. (or 61,000

Btu/hour) per square inch of blade inlet frontal area has hen tested. The gas used was air at atmospheric pressure.

In general, the high power capability per unit blade frontal area results from the very high mass flux (flow per unit frontal area). Moreover, the gas on which the rotor operates incurs a temperature rise in flow therethrough which is in direct proportion to its power absorption. With this in mind, consider the fact that the temperature rise of air moved through a radial flow motor, for example, having a peripheral speed of 250 ft./sec is about 10 F. This provides, thus, to accomplish a 200 F. rise by placing such rotors in series, approximately 20 would be needed.

In the instance of the present invention, the above mentioned high mass flux capability is utilized fully by recirculating the same gas through a heater many times so that its internal flow volume is many times that entering, or leaving, the heater. Based on this premise, to produce a 200 F. rise in temperature of gas entering a heater, using a 10 F. rise rotor, the invention provides that twenty times as much gas is continuously passed through the rotor as that which enters the heater. The invention also provides for the recirculation of the same gas through one rotor via the shortest possible route which presents the least surface for the gas to contact within the heater, and thus permits the most rapid temperature rise of the gas, an important feature of the invention.

In the instance of the embodiment here illustrated, the invention contemplates use of rotors the blades of which are radially directed from a hub to project in a recirculating flow path. Also interposed in such flow path are stator blades, the purpose of which shall be further described. In the one case the stator blades are contemplated as being in a non-planar relation to the rotor blades while in the modification there is a co-planar relation of the stator and rotor blades.

Referring now more particularly to FIG. 1 of the drawings, we here see the use of an axial flow type rotor including radially directed blades 33 on the hub 34. The rotor is peripherally contained by a housing 39 having a generally toroidal shape. The housing 30 is open at its inner side to accommodate the projection therein of the rotor blade 33. A toroidal shaped body 31 is supported centrally of the housing 30 by means of round or streamlined pins 32 secured respectively to the body 31 and the housing 30 by welding or other suitable means. So supported, the body 31 defines there-about a fixed flow path 36 having a section common to a tubular passage which is defined between a housing 3 9 for the rotor hub, which housing is tubular, and tubular projections at the opening to the housing 30 which are concentric to the housing 39. The housing 39, noting FIG. 1 of the drawings, includes spaced sections to accommodate the projection therefrom of the rotor blades 33.

As shown in the drawings, the blades 33 are driven through the flow path 315 through the medium of the hub 34- to which they mount. A row of stator blades 35 are fixed between the body 31 and the rotor housing on the output side of the blades 33 to operate in a manner to be further described.

While inlet vanes are not shown in this embodiment of the invention, they may be used faced to the side of the rotor blades 33 opposite that occupied by the stator blades 35. The inlet vanes will be used only if required to permit operation of the included rotor at a lower rpm.

In this embodiment of the invention air is recirculated through the path indicated by the arrow 36 in FIG. 1 to communicate and mix with air drawn through the d inlet 37 of the aforementioned tubular passage by the spinning rotor blades 33. In operation, the drive of the blades 33 pulls air in through the inlet 37, acts on the air to add energy to this gas to thereby raise its temperature. The following stator vanes 35 function to remove angular velocity from the driven gas and to convert it to static pressure and thereby increase such pressure at this point. By the construction and arrangement illustrated, only a fraction of the gas so heated can exit through the heater outlet 38 while the majority and remainder is caused to recirculate through the flow path 36 and mix with a fraction of air drawn in by the rotor 33 which corresponds to that discharged through the outlet 33 previously described. As will be obvious there is a continued recycling action of the majority of the heated gas due to the fractional discharge in any one pass. In each recycling pass, the air achieves an additional increment of heat. It is to be remembered that the flow of gas recirculated through the path 36 is at all times under the influence of the static pressure factor introduced in the flowing air as it passes the stator blades 35.

An iris diaphragm control valve may be included in the outlet 38. However, it would be preferable to communicate the outlet 38 with a small cylindrical tube and locate a butterfly type control valve therein. One may also place a recirculation control valve of the iris diaphragm type between blades 33 and 35. These valves are utilized as described in applicants co-pending parent application for control of temperature. However, for this embodiment of the invention here described the temperature of the delivered air can be better controlled by controlling the speed of the rotor unit including the hub 34 and blades 33.

It is to be noted that in the particular form of embodiment shown in PEG. 1 of the drawings, the rotor blades and stator blades are in any event in a nonplanar relation.

The modified embodiment of the invention as shown in FIG. 2 of the drawings reveals, in schematic fashion, a fan-like unit 46 including blades 41 which provide a rotor element eccentrically positioned within a cylindrically formed housing 43, the sides of which are flat. At its periphery, the housing d3 includes a tangentially oriented inlet 45 and, spaced therefrom, a tangentially oriented outlet 47. Note that the inlet and outlet are relatively closely spaced. It may be seen from the draw ings, that in this instance, they both lie within a 90 interval of the housing periphery.

Fixed between the walls of the housing 43 on the outlet side of the blades 41 which radially project from the fan body is an arcuate row of spaced stator blades 4-4. The blades 44 here again perform the function of stator vanes operating to remove angular velocity from air delivered thereto and to convert it to static pressure. The objective is to increase the existing static pressure at this point in the cycle of operation of the heater.

On rotation of the fan 40, the blades 41 drive air, including a component drawn in through the inlet 4-5, in a circular path from the inlets and in the general direction of the outlet 47. This air is driven to and through the stator blades 44 relatively adjacent the outlet. A portion of the air is permitted to exit through the limited outlet 47 adjacent the stator blades while the blades 44 do in fact direct the major portion of the air to recirculate back towards the inlet. Of course, in arriving to and being delivered from the stator blades there has been an increment of heat added to the air which recireulates.

The air is recirculated in an arcuate path back towards the inlet 45 adjacent where it mixes with a fraction of fresh air drawn through the inlet by the moving rotor 40 including its radially projected blades 41. Again the .amount of fresh ,air drawn is limited by the amount of heated air discharged. The mixed air is then picked up once more by the blades 41 to move through another cycle as described, during which an additional increment of heat is added to the recirculated air. As shown in FIG. 2 of the drawings, a valve member 48 is pivoted between the walls of the housing 43 at one end of the arcuate row of spaced stator blades, which end is remote from the outlet 47. The adjustment of this valve 43 to vary the recirculation passage provides a control of the amount of air which is recirculated and there for a control of the temperature rise produced in movement of a mass of air through the described heater unit.

The heater unit as revealed in FIG. 2 of the drawings has what may be seen to be the utmost simplicity in its design features and is of a most economical construction.

If the heater in accordance with the invention must be operated at very high temperatures, it may be necessary to cool the central body portions thereof such as the body 31 in the device of FIG. 1. In some instances it may be well to cool the fan or rotor blades. The central bodies may be cooled in either case by directing gas through openings in their body walls. Where hollow fan or rotor blades are employed, openings may be made in these elements to provide for flow of cooling gas theret'nrough in any suitable manner. This cooling gas may also serve as a portion of the gas to be heated.

While no insulation has been shown in the devices of the invention illustrated, this is purely an optical design element and may be employed in the areas necessary, dependent on the particular application. In reference to the material to be employed for the invention embodiments, the material to be used is not critical as long as it will withstand heat and provide a substantially smooth surface to insure a low friction on flow of gas thereabout. As a matter of fact, the entire heater of the invention can be made of metal.

In utilizing the invention embodiment of FIG. 1 as herein described, one may shroud portions of the blades 33 in a manner as described in the aforementioned parent application and with similar results. This modification is contemplated as lying within the scope of this disclosure.

The basic aspects of the invention embodiments above described should make it clearly evident that they contemplate both economy and efiiciency in the art.

In summary, in utilizing the invention principles, one can have a fully controlled recirculation of air or other gas for heating purposes as well as a balanced control of power absorption by the rotor unit utilized and thereby of the increment of heat added to air or other gas as it flows by the rotor blades. Further, the use of the stator blades will in any event cause recirculation in each pass of the air or gas through the designated path to be at high speed and produce static pressure in amounts to overcome the frictional resistance in the heater structure per so. It is a significant feature of the invention embodiments that they can reach their designed operating etficiency in a matter of seconds after starting.

From the above description it will be apparent that there is thus provided a device of the character described possessing the particular features of advantage before enumerated as desirable, but which obviously is susceptible of modification in its form, proportions, detail construction and arrangement of parts without departing from the principle involved or sacrificing any of its advantages.

While in order to comply with the statute the invention has been described in language more or less specific as to structural features, it is to be understood that the invention is not limited to the specific features shown, but that the means and construction herein disclosed comprise but one of several modes of putting the invention into effect, and the invention is therefore claimed in any of its forms or modifications within the legitimate and valid scope of the appended claims.

Having thus described my invention, I claim:

1. A gas heater including a housing having means defining therein a continuous flow path, an inlet to said flow path and an outlet therefrom, said heater comprising a rotor the vanes of which are driven through a portion of said flow path and stator vanes positioned in said flow path relatively adjacent said outlet, said outlet providing for a limited discharge of gas from said flow path fractionally related to the gas driven in recirculating fashion through said flow path by said rotor vanes, the rotor adding an increment of heat to the recirculating gas in each cycle thereby, the vanes of said rotor extending radially, generally co-planar with its hub portion, and said stator vanes being arranged to influence a high speed recirculation of gas through said flow path.

2. A heater as described in claim .1 characterized by said rotor vanes being oriented and arranged to move in a plane transverse to said flow path.

3. A heater as described in claim 1 characterized by said rotor vanes being arranged to move through a longitudinally extended portion of said flow path.

4. A heater as in claim 1 characterized by said stator vanes occupying a plane generally parallel to that of said rotor vanes.

5. A heater as in claim 1 characterized -by said rotor vanes moving in said flow path immediately adjacent said inlet to draw gas to said flow path to the degree permitted by the amount of gas discharged through said outlet.

6. A heater as described in claim 5 characterized by said stator vanes being at least in part positioned immediately adjacent to the outlet from said flow path.

7. A gas heater as described in claim 1 characterized by said housing means including concentric bodies defining said continuous flow path and providing thereby for gas to flow in a recirculating fashion about the inner said bodies, and a housing for the hub portion of said rotor providing for projecting of the rotor vanes therefrom into said continuous flow path in relatively adjacent relation to said inlet, said rotor housing in part defining said inlet and outlet.

8. A gas heater as described in claim 7 characterized by said inlet and said outlet sharing a common opening to said flow path, being directly aligned and having intermediately thereof said rotor vanes and stator vanes in direct alignment therewith.

9. A gas heater as described in claim 1 characterized by said housing forming a substantially cylindrical hollow chamber and the periphery thereof including said inlet and, angularly spaced therefrom, said outlet, said rotor being positioned between the sides of said housing in a relation offset from its center, the portion of the chamber wall between said inlet and outlet being relatively adjacent a peripheral portion of said rotor, at flow path being defined in said chamber which extends peripherally of said rotor between said inlet and said outlet, said stator vanes being positioned in said path adjacent the outlet for receiving gas delivered from said rotor vanes to direct a major portion thereof back to said inlet to recirculate through said rotor and means in the path of the recirculated gas for controlling the movement of gas thereby.

10. A gas heater as in claim 1 characterized by said housing having a generally toroidal shape and including therein a toroidal body supported in spaced relation thereto to define the continuous flow path thereabout, said vaned rotor consisting of a fan the hub of which mounts a plurality of impeller blades, said toroidal housing having an opening in its inner wall accommodating the projection therethrough of said impeller blades and said stator blades, the inlet to said flow path being in advance of said impeller blades and the outlet immediately following said stator blades, said stator blades constituting the vanes formed to induce a high speed recirculation of gas delivered by the impeller blades, there being means in said outlet for limiting the discharge of heated gas therethrough.

11. A gas heater as in claim 1 characterized by said vaned rotor having the vanes thereof on its periphery and said stator vanes consisting of a series of blades fixed in said housing positioned immediately about a portion of the rotor blades, substantially co-planar therewith, the outlet from said housing being relatively adjacent one end of said fixed blades, a valve bridging said housing adjacent the other end of said fixed blades, the inlet being positioned adjacent a portion of said rotor for a delivery of gas thereto, the rotor blades imparting an angular velocity to said gas to raise its temperature and deliver it to and through said fixed blades adjacent said outlet to have a fractional discharge thereof through said outlet and the balance influenced to recirculate at high speed by said fixed blades.

12. A gas heater including a housing providing means defining therein a continuous flow path, an inlet to said flow path and an outlet therefrom, said heater comprising a rotor the vanes of which are driven through a portion of said flow path and stator vanes positioned in said flow path in axial alignment with said rotor vanes, said stator vanes being positioned in said flow path relatively adjacent said outlet, said outlet providing means for limited discharge of gas from said flow path fractionally related to gas driven in recirculating fashion through said flow path by said rotor, the rotor vanes adding increments of heat to the recirculating gas in each cycle thereby and said stator vanes being arranged to influence a high speed recirculation of gas not discharged through said flow path.

13. A gas heater including a housing providing means defining therein a chamber, a rotor mounted in an eccentric position in said chamber, between the side walls thereof, to have a portion of radially projected vanes thereon move in an area adjacent a peripheral wall portion of said chamber, an inlet to said chamber to one end of said peripheral wall portion and an outlet from said chamber adjacent the other end thereof, the rotor vanes be ing arranged to pick up gas from said inlet and deliver it in an arcuate path in the direction of said outlet and stator vanes, positioned at least in part adjacent said outlet, arcuately extending about said rotor in said housing, said stator vanes providing for recirculation of a major portion of the gas delivered thereto through an arcuate path back in the direction of said inlet and said outlet providing means for limiting the discharge of heated gas from said housing.

References Cited by the Examiner UNITED STATES PATENTS 1,149,938 8/1915 Nagelvoort. 1,161,116 11/1915 Ehrhart. 1,161,117 11/1915 Ehrhart. 2,537,800 1/1951 Stoeckly.

CHARLES J. MYHRE, Primary Examiner. 

1. A GAS HEATER INCLUDING A HOUSING HAVING MEANS DEFINING THEREIN A CONTINUOUS FLOW PATH, AN INLET TO SAID FLOW PATH AND AN OUTLET THEREFROM, SAID HEATER COMPRISING A ROTOR THE VANES OF WHICH ARE DRIVEN THROUGH A PORTION OF SAID FLOW PATH AND STATOR VANES POSITIONED IN SAID FLOW PATH RELATIVELY ADJACENT SAID OUTLET, SAID OUTLET PROVIDING FOR A LIMITED DISCHARGE OF GAS FROM SAID FLOW PATH FRACTIONALLY RELATED TO THE GAS DRIVEN IN RECIRCULATING FASHION THROUGH SAID FLOW PATH BY SAID ROTOR VANES, THE ROTOR ADDING AN INCREMENT OF HEAT TO THE RECIRCULATING GAS IN EACH CYCLE THEREBY, THE VANES OF SAID ROTOR EXTENDING RADIALLY, GENERALLY CO-PLANAR WITH ITS HUB PORTION, AND SAID STATOR VANES BEING ARRANGED TO INFLU- 